diff --git a/gcc/elna-generic.cc b/gcc/elna-generic.cc
index 6626adb..620c32c 100644
--- a/gcc/elna-generic.cc
+++ b/gcc/elna-generic.cc
@@ -154,7 +154,9 @@ namespace elna::gcc
             }
             else if (constant_expression != boolean_true_node)
             {
-                this->current_expression = call_built_in(call_location, "__builtin_trap", void_type_node);
+                tree assert_expression = call_built_in(call_location, "__builtin_trap", void_type_node);
+                this->current_expression = build3(COND_EXPR, void_type_node, this->current_expression,
+                        NULL_TREE, assert_expression);
             }
             else
             {
@@ -486,7 +488,6 @@ namespace elna::gcc
         {
             gcc_unreachable();
         }
-
         if (left_type == elna_bool_type_node)
         {
             return build2_loc(expression_location, logical_code, elna_bool_type_node, left, right);
@@ -497,8 +498,7 @@ namespace elna::gcc
         }
         else
         {
-            error_at(expression_location,
-                    "Invalid operands of type '%s' and '%s' for operator %s",
+            error_at(expression_location, "Invalid operands of type '%s' and '%s' for operator %s",
                     print_type(left_type).c_str(), print_type(right_type).c_str(),
                     elna::boot::print_binary_operator(expression->operation()));
             return error_mark_node;
@@ -810,21 +810,18 @@ namespace elna::gcc
             this->current_expression = error_mark_node;
             return;
         }
-        if (this->current_expression != elna_word_type_node)
-        {
-            this->current_expression = convert(elna_word_type_node, this->current_expression);
-        }
-        tree offset = build2(MINUS_EXPR, elna_word_type_node, this->current_expression, size_one_node);
+        tree offset = fold_convert(elna_word_type_node, this->current_expression);
 
         if (TREE_CODE(TREE_TYPE(designator)) == ARRAY_TYPE)
         {
             tree element_type = TREE_TYPE(TREE_TYPE(designator));
 
             this->current_expression = build4_loc(location,
-                    ARRAY_REF, element_type, designator, offset, NULL_TREE, NULL_TREE);
+                    ARRAY_REF, element_type, designator, offset, size_one_node, NULL_TREE);
         }
         else if (TREE_TYPE(designator) == elna_string_type_node)
         {
+            offset = build2(MINUS_EXPR, elna_word_type_node, offset, size_one_node);
             tree string_ptr = build3_loc(location, COMPONENT_REF, TREE_TYPE(elna_string_ptr_field_node),
                     designator, elna_string_ptr_field_node, NULL_TREE);
 
diff --git a/gcc/elna-tree.cc b/gcc/elna-tree.cc
index d00a39a..7860d75 100644
--- a/gcc/elna-tree.cc
+++ b/gcc/elna-tree.cc
@@ -21,7 +21,6 @@ along with GCC; see the file COPYING3.  If not see
 
 #include "function.h"
 #include "stor-layout.h"
-#include "fold-const.h"
 #include "diagnostic-core.h"
 
 namespace elna::gcc
@@ -248,9 +247,8 @@ namespace elna::gcc
 
     tree build_static_array_type(tree type, const std::uint64_t size)
     {
-        tree lower_bound = build_int_cst_type(integer_type_node, 0);
         tree upper_bound = build_int_cst_type(integer_type_node, size);
-        tree range_type = build_range_type(integer_type_node, lower_bound, upper_bound);
+        tree range_type = build_range_type(integer_type_node, size_one_node, upper_bound);
 
         return build_array_type(type, range_type);
     }
diff --git a/include/elna/gcc/elna-tree.h b/include/elna/gcc/elna-tree.h
index e605d51..f1402a7 100644
--- a/include/elna/gcc/elna-tree.h
+++ b/include/elna/gcc/elna-tree.h
@@ -25,6 +25,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree.h"
 #include "tree-iterator.h"
 #include "stringpool.h"
+#include "fold-const.h"
 
 #include "elna/boot/ast.h"
 #include "elna/boot/symbol.h"
@@ -97,6 +98,8 @@ namespace elna::gcc
         tree fndecl_type = build_function_type(return_type, TYPE_ARG_TYPES(*builtin));
         tree builtin_addr = build1_loc(call_location, ADDR_EXPR, build_pointer_type(fndecl_type), *builtin);
 
-        return build_call_nary(return_type, builtin_addr, sizeof...(Args), arguments...);
+        tree argument_trees[sizeof...(Args)] = {arguments...};
+
+        return fold_build_call_array(return_type, builtin_addr, sizeof...(Args), argument_trees);
     }
 }
diff --git a/source/main.elna b/source/main.elna
index f6c7ce7..0f3d001 100644
--- a/source/main.elna
+++ b/source/main.elna
@@ -196,10 +196,10 @@ begin
   end;
   while value <> 0 do
     digit := value % 10;
-	value := value / 10;
+    value := value / 10;
 
-	buffer[n] := cast(cast('0': Int) + digit: Char);
-	n := n - 1u
+    buffer[n] := cast(cast('0': Int) + digit: Char);
+    n := n - 1u
   end;
   while n < 10u do
     n := n + 1u;
@@ -309,7 +309,7 @@ begin
 
   if source_file^.index > source_file^.size then
     source_file^.size := fread(cast(@source_file^.buffer: Pointer), 1u, 1024u, source_file^.handle);
-	  source_file^.index := 1u
+    source_file^.index := 1u
   end;
 
   return source_file^.size = 0u
@@ -366,41 +366,41 @@ var
   successful: Bool;
 begin
   if escape = 'n' then
-	result^ := '\n';
-	successful := true
+    result^ := '\n';
+    successful := true
   elsif escape = 'a' then
-	result^ := '\a';
-	successful := true
+    result^ := '\a';
+    successful := true
   elsif escape = 'b' then
-	result^ := '\b';
-	successful := true
+    result^ := '\b';
+    successful := true
   elsif escape = 't' then
-	result^ := '\t';
-	successful := true
+    result^ := '\t';
+    successful := true
   elsif escape = 'f' then
-	result^ := '\f';
-	successful := true
+    result^ := '\f';
+    successful := true
   elsif escape = 'r' then
-	result^ := '\r';
-	successful := true
+    result^ := '\r';
+    successful := true
   elsif escape = 'v' then
-	result^ := '\v';
-	successful := true
+    result^ := '\v';
+    successful := true
   elsif escape = '\\' then
-	result^ := '\\';
-	successful := true
+    result^ := '\\';
+    successful := true
   elsif escape = '\'' then
-	result^ := '\'';
-	successful := true
+    result^ := '\'';
+    successful := true
   elsif escape = '"' then
-	result^ := '"';
-	successful := true
+    result^ := '"';
+    successful := true
   elsif escape = '?' then
-	result^ := '\?';
-	successful := true
+    result^ := '\?';
+    successful := true
   elsif escape = '0' then
-	result^ := '\0';
-	successful := true
+    result^ := '\0';
+    successful := true
   else
     successful := false
   end;
@@ -417,8 +417,8 @@ begin
 
     if current = '\n' then
       source_code_break(source_code)
-	end;
-	source_code_advance(source_code)
+    end;
+    source_code_advance(source_code)
   end
 end;
 
@@ -433,7 +433,7 @@ var
 begin
   while ~source_code_empty(source_code) & lexer_is_ident(source_code_head(source_code^)) do
     string_buffer_push(token_content, source_code_head(source_code^));
-	source_code_advance(source_code)
+    source_code_advance(source_code)
   end
 end;
 
@@ -445,15 +445,15 @@ begin
 
   while ~source_code_empty(source_code) & trailing < 2u do
     if source_code_head(source_code^) = '*' then
-	  string_buffer_push(token_content, '*');
-	  trailing := 1u
-	elsif source_code_head(source_code^) = ')' & trailing = 1u then
+      string_buffer_push(token_content, '*');
+      trailing := 1u
+    elsif source_code_head(source_code^) = ')' & trailing = 1u then
       string_buffer_pop(token_content, 1u);
-	  trailing := 2u
-	else
-	  string_buffer_push(token_content, source_code_head(source_code^));
-	  trailing := 0u
-	end;
+      trailing := 2u
+    else
+      string_buffer_push(token_content, source_code_head(source_code^));
+      trailing := 0u
+    end;
     source_code_advance(source_code)
   end;
 
@@ -471,9 +471,9 @@ begin
       source_code_advance(source_code);
 
       successful := ~source_code_empty(source_code) & lexer_escape(source_code_head(source_code^), token_content)
-	else
+    else
       token_content^ := source_code_head(source_code^);
-	  successful := true
+      successful := true
     end
   end;
   if successful then
@@ -524,64 +524,64 @@ var
   current_token: Token;
 begin
   if token_content = "if" then
-	current_token.kind := TokenKind._if
+    current_token.kind := TokenKind._if
   elsif token_content = "then" then
-	current_token.kind := TokenKind._then
+    current_token.kind := TokenKind._then
   elsif token_content = "else" then
-	current_token.kind := TokenKind._else
+    current_token.kind := TokenKind._else
   elsif token_content = "elsif" then
-	current_token.kind := TokenKind._elsif
+    current_token.kind := TokenKind._elsif
   elsif token_content = "while" then
-	current_token.kind := TokenKind._while
+    current_token.kind := TokenKind._while
   elsif token_content = "do" then
-	current_token.kind := TokenKind._do
+    current_token.kind := TokenKind._do
   elsif token_content = "proc" then
-	current_token.kind := TokenKind._proc
+    current_token.kind := TokenKind._proc
   elsif token_content = "begin" then
-	current_token.kind := TokenKind._begin
+    current_token.kind := TokenKind._begin
   elsif token_content = "end" then
-	current_token.kind := TokenKind._end
+    current_token.kind := TokenKind._end
   elsif token_content = "extern" then
-	current_token.kind := TokenKind._extern
+    current_token.kind := TokenKind._extern
   elsif token_content = "const" then
-	current_token.kind := TokenKind._const
+    current_token.kind := TokenKind._const
   elsif token_content = "var" then
-	current_token.kind := TokenKind._var
+    current_token.kind := TokenKind._var
   elsif token_content = "case" then
-	current_token.kind := TokenKind._case
+    current_token.kind := TokenKind._case
   elsif token_content = "of" then
-	current_token.kind := TokenKind._of
+    current_token.kind := TokenKind._of
   elsif token_content = "type" then
-	current_token.kind := TokenKind._type
+    current_token.kind := TokenKind._type
   elsif token_content = "record" then
-	current_token.kind := TokenKind._record
+    current_token.kind := TokenKind._record
   elsif token_content = "union" then
-	current_token.kind := TokenKind._union
+    current_token.kind := TokenKind._union
   elsif token_content = "true" then
-	current_token.kind := TokenKind.boolean;
-	current_token.value.boolean_value := true
+    current_token.kind := TokenKind.boolean;
+    current_token.value.boolean_value := true
   elsif token_content = "false" then
-	current_token.kind := TokenKind.boolean;
-	current_token.value.boolean_value := false
+    current_token.kind := TokenKind.boolean;
+    current_token.value.boolean_value := false
   elsif token_content = "nil" then
-	current_token.kind := TokenKind.null
+    current_token.kind := TokenKind.null
   elsif token_content = "or" then
-	current_token.kind := TokenKind._or
+    current_token.kind := TokenKind._or
   elsif token_content = "return" then
-	current_token.kind := TokenKind._return
+    current_token.kind := TokenKind._return
   elsif token_content = "cast" then
-	current_token.kind := TokenKind._cast
+    current_token.kind := TokenKind._cast
   elsif token_content = "defer" then
-	current_token.kind := TokenKind._defer
+    current_token.kind := TokenKind._defer
   elsif token_content = "program" then
-	current_token.kind := TokenKind._program
+    current_token.kind := TokenKind._program
   elsif token_content = "module" then
     current_token.kind := TokenKind._module
   elsif token_content = "import" then
     current_token.kind := TokenKind._import
   else
-	current_token.kind := TokenKind.identifier;
-	current_token.value.string := string_dup(token_content)
+    current_token.kind := TokenKind.identifier;
+    current_token.value.string := string_dup(token_content)
   end;
 
   return current_token
@@ -611,162 +611,162 @@ begin
     lexer_identifier(@source_code, token_buffer);
     current_token := lexer_categorize(string_buffer_clear(token_buffer))
   elsif first_char = '#' then
-	source_code_advance(@source_code);
-	lexer_identifier(@source_code, token_buffer);
+    source_code_advance(@source_code);
+    lexer_identifier(@source_code, token_buffer);
 
-	current_token.kind := TokenKind.trait;
-	current_token.value.string := string_dup(string_buffer_clear(token_buffer))
+    current_token.kind := TokenKind.trait;
+    current_token.value.string := string_dup(string_buffer_clear(token_buffer))
   elsif is_digit(first_char) then
-	lexer_number(@source_code, @current_token.value.int_value);
+    lexer_number(@source_code, @current_token.value.int_value);
 
-	if source_code_expect(@source_code, 'u') then
-	  current_token.kind := TokenKind.word;
-      source_code_advance(@source_code)
-	else
-	  current_token.kind := TokenKind.integer
-	end
+    if source_code_expect(@source_code, 'u') then
+      current_token.kind := TokenKind.word;
+        source_code_advance(@source_code)
+    else
+      current_token.kind := TokenKind.integer
+    end
   elsif first_char = '(' then
-	source_code_advance(@source_code);
+    source_code_advance(@source_code);
 
-	if source_code_empty(@source_code) then
-	  current_token.kind := TokenKind.left_paren
-	elsif source_code_head(source_code) = '*' then
-	  source_code_advance(@source_code);
+    if source_code_empty(@source_code) then
+      current_token.kind := TokenKind.left_paren
+    elsif source_code_head(source_code) = '*' then
+      source_code_advance(@source_code);
 
-	  if lexer_comment(@source_code, token_buffer) then
-	    current_token.value.string := string_dup(string_buffer_clear(token_buffer));
-	    current_token.kind := TokenKind.comment
-	  else
-	    current_token.kind := TokenKind.unknown
-	  end
-	else
-	  current_token.kind := TokenKind.left_paren
-	end
+      if lexer_comment(@source_code, token_buffer) then
+        current_token.value.string := string_dup(string_buffer_clear(token_buffer));
+        current_token.kind := TokenKind.comment
+      else
+        current_token.kind := TokenKind.unknown
+      end
+    else
+      current_token.kind := TokenKind.left_paren
+    end
   elsif first_char = ')' then
-	current_token.kind := TokenKind.right_paren;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.right_paren;
+    source_code_advance(@source_code)
   elsif first_char = '\'' then
     source_code_advance(@source_code);
 
-	if lexer_character(@source_code, @current_token.value.char_value) & source_code_expect(@source_code, '\'') then
-		current_token.kind := TokenKind.character;
-	  source_code_advance(@source_code)
-	else
-	  current_token.kind := TokenKind.unknown
-	end
+    if lexer_character(@source_code, @current_token.value.char_value) & source_code_expect(@source_code, '\'') then
+      current_token.kind := TokenKind.character;
+      source_code_advance(@source_code)
+    else
+      current_token.kind := TokenKind.unknown
+    end
   elsif first_char = '"' then
     source_code_advance(@source_code);
-	
+
     if lexer_string(@source_code, token_buffer) then
-	  current_token.kind := TokenKind.string;
-	  current_token.value.string := string_dup(string_buffer_clear(token_buffer))
-	else
-	  current_token.kind := TokenKind.unknown
-	end
+      current_token.kind := TokenKind.string;
+      current_token.value.string := string_dup(string_buffer_clear(token_buffer))
+    else
+      current_token.kind := TokenKind.unknown
+    end
   elsif first_char = '[' then
-	current_token.kind := TokenKind.left_square;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.left_square;
+    source_code_advance(@source_code)
   elsif first_char = ']' then
-	current_token.kind := TokenKind.right_square;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.right_square;
+    source_code_advance(@source_code)
   elsif first_char = '>' then
-	source_code_advance(@source_code);
+    source_code_advance(@source_code);
 
     if source_code_empty(@source_code) then
-	  current_token.kind := TokenKind.greater_than
-	elsif source_code_head(source_code) = '=' then
-	  current_token.kind := TokenKind.greater_equal;
-	  source_code_advance(@source_code)
-	elsif source_code_head(source_code) = '>' then
-	  current_token.kind := TokenKind.shift_right;
-	  source_code_advance(@source_code)
-	else
-	  current_token.kind := TokenKind.greater_than
-	end
+      current_token.kind := TokenKind.greater_than
+    elsif source_code_head(source_code) = '=' then
+      current_token.kind := TokenKind.greater_equal;
+      source_code_advance(@source_code)
+    elsif source_code_head(source_code) = '>' then
+      current_token.kind := TokenKind.shift_right;
+      source_code_advance(@source_code)
+    else
+      current_token.kind := TokenKind.greater_than
+    end
   elsif first_char = '<' then
-	source_code_advance(@source_code);
-
-	if source_code_empty(@source_code) then
-	  current_token.kind := TokenKind.less_than
-	elsif source_code_head(source_code) = '=' then
-	  current_token.kind := TokenKind.less_equal;
-	  source_code_advance(@source_code)
-	elsif source_code_head(source_code) = '<' then
-	  current_token.kind := TokenKind.shift_left;
-	  source_code_advance(@source_code)
-	elsif source_code_head(source_code) = '>' then
-	  current_token.kind := TokenKind.not_equal;
-	  source_code_advance(@source_code)
-	else
-	  current_token.kind := TokenKind.less_than
-	end
-  elsif first_char = '=' then
-	current_token.kind := TokenKind.equal;
-	source_code_advance(@source_code)
-  elsif first_char = ';' then
-	current_token.kind := TokenKind.semicolon;
-	source_code_advance(@source_code)
-  elsif first_char = '.' then
-	current_token.kind := TokenKind.dot;
-	source_code_advance(@source_code)
-  elsif first_char = ',' then
-	current_token.kind := TokenKind.comma;
-	source_code_advance(@source_code)
-  elsif first_char = '+' then
-	current_token.kind := TokenKind.plus;
-	source_code_advance(@source_code)
-  elsif first_char = '-' then
-	source_code_advance(@source_code);
+    source_code_advance(@source_code);
 
     if source_code_empty(@source_code) then
-	  current_token.kind := TokenKind.minus
-	elsif source_code_head(source_code) = '>' then
-	  current_token.kind := TokenKind.arrow;
-	  source_code_advance(@source_code)
-	else
-	  current_token.kind := TokenKind.minus
-	end
-  elsif first_char = '*' then
-	current_token.kind := TokenKind.multiplication;
-	source_code_advance(@source_code)
-  elsif first_char = '/' then
-	current_token.kind := TokenKind.division;
-	source_code_advance(@source_code)
-  elsif first_char = '%' then
-	current_token.kind := TokenKind.remainder;
-	source_code_advance(@source_code)
-  elsif first_char = ':' then
-	source_code_advance(@source_code);
+      current_token.kind := TokenKind.less_than
+    elsif source_code_head(source_code) = '=' then
+      current_token.kind := TokenKind.less_equal;
+      source_code_advance(@source_code)
+    elsif source_code_head(source_code) = '<' then
+      current_token.kind := TokenKind.shift_left;
+      source_code_advance(@source_code)
+    elsif source_code_head(source_code) = '>' then
+      current_token.kind := TokenKind.not_equal;
+      source_code_advance(@source_code)
+    else
+      current_token.kind := TokenKind.less_than
+    end
+  elsif first_char = '=' then
+    current_token.kind := TokenKind.equal;
+    source_code_advance(@source_code)
+  elsif first_char = ';' then
+    current_token.kind := TokenKind.semicolon;
+    source_code_advance(@source_code)
+  elsif first_char = '.' then
+    current_token.kind := TokenKind.dot;
+    source_code_advance(@source_code)
+  elsif first_char = ',' then
+    current_token.kind := TokenKind.comma;
+    source_code_advance(@source_code)
+  elsif first_char = '+' then
+    current_token.kind := TokenKind.plus;
+    source_code_advance(@source_code)
+  elsif first_char = '-' then
+    source_code_advance(@source_code);
 
-	if source_code_empty(@source_code) then
-	  current_token.kind := TokenKind.colon
-	elsif source_code_head(source_code) = '=' then
-	  current_token.kind := TokenKind.assignment;
-	  source_code_advance(@source_code)
-	else
-	  current_token.kind := TokenKind.colon
-	end
+    if source_code_empty(@source_code) then
+      current_token.kind := TokenKind.minus
+    elsif source_code_head(source_code) = '>' then
+      current_token.kind := TokenKind.arrow;
+      source_code_advance(@source_code)
+    else
+      current_token.kind := TokenKind.minus
+    end
+  elsif first_char = '*' then
+    current_token.kind := TokenKind.multiplication;
+    source_code_advance(@source_code)
+  elsif first_char = '/' then
+    current_token.kind := TokenKind.division;
+    source_code_advance(@source_code)
+  elsif first_char = '%' then
+    current_token.kind := TokenKind.remainder;
+    source_code_advance(@source_code)
+  elsif first_char = ':' then
+    source_code_advance(@source_code);
+
+    if source_code_empty(@source_code) then
+      current_token.kind := TokenKind.colon
+    elsif source_code_head(source_code) = '=' then
+      current_token.kind := TokenKind.assignment;
+      source_code_advance(@source_code)
+    else
+      current_token.kind := TokenKind.colon
+    end
   elsif first_char = '^' then
-	current_token.kind := TokenKind.hat;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.hat;
+    source_code_advance(@source_code)
   elsif first_char = '@' then
-	current_token.kind := TokenKind.at;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.at;
+    source_code_advance(@source_code)
   elsif first_char = '!' then
-	current_token.kind := TokenKind.exclamation;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.exclamation;
+    source_code_advance(@source_code)
   elsif first_char = '&' then
-	current_token.kind := TokenKind.and;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.and;
+    source_code_advance(@source_code)
   elsif first_char = '~' then
-	current_token.kind := TokenKind.not;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.not;
+    source_code_advance(@source_code)
   elsif first_char = '|' then
-	current_token.kind := TokenKind.pipe;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.pipe;
+    source_code_advance(@source_code)
   else
-	current_token.kind := TokenKind.unknown;
-	source_code_advance(@source_code)
+    current_token.kind := TokenKind.unknown;
+    source_code_advance(@source_code)
   end;
 
   return current_token
@@ -785,16 +785,16 @@ begin
   lexer_spaces(@source_code);
 
   while ~source_code_empty(@source_code) do
-	current_token := lexer_next(source_code, @token_buffer);
+    current_token := lexer_next(source_code, @token_buffer);
 
-	if current_token.kind <> TokenKind.unknown then
-	  lexer_add_token(@lexer, current_token);
-      lexer_spaces(@source_code)
-	else
-	  write_s("Lexical analysis error on \"");
-	  write_c(source_code_head(source_code));
-	  write_s("\".\n")
-	end
+    if current_token.kind <> TokenKind.unknown then
+      lexer_add_token(@lexer, current_token);
+        lexer_spaces(@source_code)
+    else
+      write_s("Lexical analysis error on \"");
+      write_c(source_code_head(source_code));
+      write_s("\".\n")
+    end
   end;
 
   return lexer
@@ -824,12 +824,12 @@ begin
     elsif strcmp(parameter^, "--parse\0".ptr) = 0 then
       result^.parse := true
     elsif parameter^^ <> '-' then
-	  if result^.input <> nil then
-		write_s("Fatal error: Only one source file can be given.\n");
-		result := nil
-	  else
+      if result^.input <> nil then
+      write_s("Fatal error: Only one source file can be given.\n");
+      result := nil
+      else
         result^.input := parameter^
-	  end
+      end
     else
       write_s("Fatal error: Unknown command line options: ");
 
@@ -843,7 +843,7 @@ begin
   end;
   if result <> nil & result^.input = nil then
     write_s("Fatal error: no input files.\n");
-	result := nil
+    result := nil
   end;
 
   return result
@@ -863,151 +863,151 @@ begin
     current_token := tokens + i;
 
     case current_token^.kind of
-	  TokenKind._if:
-	    write_s("IF")
+      TokenKind._if:
+        write_s("IF")
       | TokenKind._then:
-	    write_s("THEN")
+        write_s("THEN")
       | TokenKind._else:
-	    write_s("ELSE")
+        write_s("ELSE")
       | TokenKind._elsif:
-	    write_s("ELSIF")
+        write_s("ELSIF")
       | TokenKind._while:
-	    write_s("WHILE")
+        write_s("WHILE")
       | TokenKind._do:
-	    write_s("DO")
-	  | TokenKind._proc:
-	    write_s("PROC")
-	  | TokenKind._begin:
-	    write_s("BEGIN")
-	  | TokenKind._end:
-	    write_s("END")
-   	  | TokenKind._extern:
-	    write_s("EXTERN")
-	  | TokenKind._const:
-	    write_s("CONST")
-	  | TokenKind._var:
-	    write_s("VAR")
-   	  | TokenKind._case:
-	    write_s("CASE")
-	  | TokenKind._of:
-	    write_s("OF")
-	  | TokenKind._type:
-	    write_s("TYPE")
-	  | TokenKind._record:
-	    write_s("RECORD")
-	  | TokenKind._union:
-	    write_s("UNION")
-	  | TokenKind.pipe:
-	    write_s("|")
-	  | TokenKind.to:
-	    write_s("TO")
-	  | TokenKind.boolean:
-	    write_s("BOOLEAN<");
-	    write_b(current_token^.value.boolean_value);
-	    write_c('>')
-	  | TokenKind.null:
-	    write_s("NIL")
-	  | TokenKind.and:
-	    write_s("&")
-	  | TokenKind._or:
-	    write_s("OR")
-	  | TokenKind.not:
-	    write_s("~")
-	  | TokenKind._return:
-	    write_s("RETURN")
-	  | TokenKind._cast:
-	    write_s("CAST")
-	  | TokenKind.shift_left:
-	    write_s("<<")
-	  | TokenKind.shift_right:
-	    write_s(">>")
-	  | TokenKind.identifier:
-	    write_c('<');
+        write_s("DO")
+      | TokenKind._proc:
+        write_s("PROC")
+      | TokenKind._begin:
+        write_s("BEGIN")
+      | TokenKind._end:
+        write_s("END")
+      | TokenKind._extern:
+        write_s("EXTERN")
+      | TokenKind._const:
+        write_s("CONST")
+      | TokenKind._var:
+        write_s("VAR")
+     | TokenKind._case:
+        write_s("CASE")
+      | TokenKind._of:
+        write_s("OF")
+      | TokenKind._type:
+        write_s("TYPE")
+      | TokenKind._record:
+        write_s("RECORD")
+      | TokenKind._union:
+        write_s("UNION")
+      | TokenKind.pipe:
+        write_s("|")
+      | TokenKind.to:
+        write_s("TO")
+      | TokenKind.boolean:
+        write_s("BOOLEAN<");
+        write_b(current_token^.value.boolean_value);
+        write_c('>')
+      | TokenKind.null:
+        write_s("NIL")
+      | TokenKind.and:
+        write_s("&")
+      | TokenKind._or:
+        write_s("OR")
+      | TokenKind.not:
+        write_s("~")
+      | TokenKind._return:
+        write_s("RETURN")
+      | TokenKind._cast:
+        write_s("CAST")
+      | TokenKind.shift_left:
+        write_s("<<")
+      | TokenKind.shift_right:
+        write_s(">>")
+      | TokenKind.identifier:
+        write_c('<');
         write_s(current_token^.value.string);
-	    write_c('>')
-	  | TokenKind.trait:
-	    write_c('#');
-		write_s(current_token^.value.string)
-	  | TokenKind.left_paren:
-	    write_s("(")
-	  | TokenKind.right_paren:
-	    write_s(")")
-	  | TokenKind.left_square:
-	    write_s("[")
-	  | TokenKind.right_square:
-	    write_s("]")
-	  | TokenKind.greater_equal:
-	    write_s(">=")
-	  | TokenKind.less_equal:
-	    write_s("<=")
-	  | TokenKind.greater_than:
-	    write_s(">")
-	  | TokenKind.less_than:
-	    write_s("<")
-	  | TokenKind.equal:
-	    write_s("=")
-	  | TokenKind.not_equal:
-	    write_s("<>")
-	  | TokenKind.semicolon:
-	    write_c(';')
-	  | TokenKind.dot:
-	    write_c('.')
-	  | TokenKind.comma:
-	    write_c(',')
-	  | TokenKind.plus:
-	    write_c('+')
-	  | TokenKind.minus:
-	    write_c('-')
-	  | TokenKind.multiplication:
-	    write_c('*')
-	  | TokenKind.division:
-	    write_c('/')
-	  | TokenKind.remainder:
-	    write_c('%')
-	  | TokenKind.assignment:
-	    write_s(":=")
-	  | TokenKind.colon:
-	    write_c(':')
-	  | TokenKind.hat:
-	    write_c('^')
-	  | TokenKind.at:
-	    write_c('@')
-	  | TokenKind.comment:
-	    write_s("(* COMMENT *)")
-	  | TokenKind.integer:
-	    write_c('<');
+        write_c('>')
+      | TokenKind.trait:
+        write_c('#');
+        write_s(current_token^.value.string)
+      | TokenKind.left_paren:
+        write_s("(")
+      | TokenKind.right_paren:
+        write_s(")")
+      | TokenKind.left_square:
+        write_s("[")
+      | TokenKind.right_square:
+        write_s("]")
+      | TokenKind.greater_equal:
+        write_s(">=")
+      | TokenKind.less_equal:
+        write_s("<=")
+      | TokenKind.greater_than:
+        write_s(">")
+      | TokenKind.less_than:
+        write_s("<")
+      | TokenKind.equal:
+        write_s("=")
+      | TokenKind.not_equal:
+        write_s("<>")
+      | TokenKind.semicolon:
+        write_c(';')
+      | TokenKind.dot:
+        write_c('.')
+      | TokenKind.comma:
+        write_c(',')
+      | TokenKind.plus:
+        write_c('+')
+      | TokenKind.minus:
+        write_c('-')
+      | TokenKind.multiplication:
+        write_c('*')
+      | TokenKind.division:
+        write_c('/')
+      | TokenKind.remainder:
+        write_c('%')
+      | TokenKind.assignment:
+        write_s(":=")
+      | TokenKind.colon:
+        write_c(':')
+      | TokenKind.hat:
+        write_c('^')
+      | TokenKind.at:
+        write_c('@')
+      | TokenKind.comment:
+        write_s("(* COMMENT *)")
+      | TokenKind.integer:
+        write_c('<');
         write_i(current_token^.value.int_value);
-	    write_c('>')
-	  | TokenKind.word:
-	    write_c('<');
+        write_c('>')
+      | TokenKind.word:
+        write_c('<');
         write_i(current_token^.value.int_value);
-	    write_s("u>")
-	  | TokenKind.character:
-	    write_c('<');
+        write_s("u>")
+      | TokenKind.character:
+        write_c('<');
         write_i(cast(current_token^.value.char_value: Int));
-	    write_s("c>")
-	  | TokenKind.string:
-	    write_s("\"...\"")
-	  | TokenKind._defer:
-	    write_s("DEFER")
-	  | TokenKind.exclamation:
-	    write_c('!')
-	  | TokenKind.arrow:
-	    write_s("->")
-	  | TokenKind._program:
-	    write_s("PROGRAM")
-	  | TokenKind._module:
-		write_s("MODULE")
-	  | TokenKind._import:
-		write_s("IMPORT")
-	  else
-	    write_s("UNKNOWN<");
-	    write_i(cast(current_token^.kind: Int));
-	    write_c('>')
-	end;
-	write_c(' ');
+        write_s("c>")
+      | TokenKind.string:
+        write_s("\"...\"")
+      | TokenKind._defer:
+        write_s("DEFER")
+      | TokenKind.exclamation:
+        write_c('!')
+      | TokenKind.arrow:
+        write_s("->")
+      | TokenKind._program:
+        write_s("PROGRAM")
+      | TokenKind._module:
+      write_s("MODULE")
+      | TokenKind._import:
+      write_s("IMPORT")
+      else
+        write_s("UNKNOWN<");
+        write_i(cast(current_token^.kind: Int));
+        write_c('>')
+    end;
+    write_c(' ');
 
-	i := i + 1u
+    i := i + 1u
   end;
   write_c('\n')
 end;
@@ -1052,22 +1052,22 @@ begin
   if return_code = 0 then
     source_file := read_source(command_line^.input);
 
-	if source_file = nil then
-	  perror(command_line^.input);
-	  return_code := 3
-	end
+    if source_file = nil then
+      perror(command_line^.input);
+      return_code := 3
+    end
   end;
 
   if return_code = 0 then
     defer
-	  fclose(source_file^.handle)
-	end;
+      fclose(source_file^.handle)
+    end;
 
-	source_code.position := TextLocation(1u, 1u);
-	source_code.input := cast(source_file: Pointer);
-	source_code.empty := source_file_empty;
-	source_code.head := source_file_head;
-	source_code.advance := source_file_advance;
+    source_code.position := TextLocation(1u, 1u);
+    source_code.input := cast(source_file: Pointer);
+    source_code.empty := source_file_empty;
+    source_code.head := source_file_head;
+    source_code.advance := source_file_advance;
 
     return_code := compile_in_stages(command_line, source_code)
   end;